#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main() {
	int arr[4] = { 0 };
	int max = 0;
	for (int i = 0; i < 4; i++) {
		scanf("%d", &arr[i]);
		if (max <= arr[i]) {
			max = arr[i];
		}
	}
	printf("%d", max);
	return 0;
}